• 전기의세계
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• v.31 no.1
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• pp.68-73
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• 1982

An accurate mathematical model of permanent magnet stepping motor is proposed. On the basis of this model, micro-stepping control is experimented. A comparison is made between the Data experimented by micro-stepping control and the data predicted by the proposed model and by Leenhouts' earlier model. The result shows that the proposed model is more accurate than the earlier model, and micro-stepping can be attained by dividing a given step electrically, without adding much complexity to the control circuit, or degrading the speed of stepping motors.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.12
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• pp.1624-1634
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• 1997

A numerical study on two-dimensional unsteady transonic cascade flow has been performed by adopting dual time stepping and the k-.omega. turbulence model. An explicit 4 stage Runge-Kutta scheme for the compressible Navier-Stokes equations and an implicit Gauss-Seidel iteration scheme for the k-.omega. turbulence model are proposed for fictitious time stepping. This mixed time stepping scheme ensures the stability of numerical computation and exhibits a good convergence property with less computation time. Typical steady-state convergence accelerating schemes such as local time stepping, residual smoothing and multigrid combined with dual time stepping shows good convergence properties. Numerical results are presented for unsteady laminar flow past a cylinder and turbulent shock buffeting problem for bicircular arc cascade flow is discussed.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.1
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• pp.124-132
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• 2002

Daebangpung-tang(DBPT) is one of the prescriptions used for the treatment of rheumatoid arthritis(RA) in oriental medicine. The present study aimed to examine the analgesic effect of DBPT on a rat model of CFA-induced arthritis, which is not identical to human auto-immune arthritis although it does have many features in common with RA, and the relation between DBPT-induced analgesia and steroid hormones. CFA-induced arthritis rat model used to test the effect of DBPT was chronic pain model. After the induction of arthritis, rats subsequently showed a reduced stepping force of the affected limb for at least the next 18 days. The reduced stepping force of the limb was presumably due to a painful knee, since oral injection of indomethacin produced temporary improvement of weight bearing. DBPT dissolved in water was orally administrated. After the treatment, behavioral tests measuring stepping force were periodically conducted during the next 4 hours. DBPT produce significant improvement of stepping force of the hindlimb affected by the arthritis lasting at least 3 hours. The magnitude of this improvement was equivalent to that obtained after an oral injection of 3mg/kg of indomethacin and this improvement of stepping force was interpreted as an analgesic effect. The reduced stepping force was divided into three stages(10-30g, 30-50g, and 50-70g). All experiments was performed at 50-70g of stepping force, since both DBPT and indomethacin showed the most excellent analgesic effect at 50-70g of stepping force. DBPT produced the improvement of stepping force of the affected hindlimb in a dose-dependent manner and showed analgesic effect on neuropathic pain as well. DBPT-induced analgesic effect could not be blocked by systemic injection of steroid antagonist mifepristone. The present study suggest 1) that DBPT produces a potent analgesic effect on the chronic knee arthritis pain model in the rat and 2) that steroids system does not mediate DBPT-induced analgesia.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1219-1226
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• 2017

This paper presents the hybrid stepping machine for linear oscillating generators. The focus of the work is the suggestion of the improved model through the comparison of proposed models ; new flux concentrating PMs mover of the hybrid stepping generator is proposed based on the symmetrical and non-symmetrical stator cores of the surface mounted PMs mover, and non-slanted PMs and slanted PMs of the flux concentrating PMs mover. It is achieved using equivalent magnetic circuit considering leakage elements. Finally, this study suggests new hybrid stepping structure of linear oscillating generator.

• Korean Journal of Acupuncture
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• v.21 no.4
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• pp.83-99
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• 2004

Objectives : Daeganghwal-Tang(DGHT) is one of the prescriptions used for the treatment of rheumatoid arthritis(RA) in oriental medicine. The present study aimed to examine the analgesic effect of DGHT on a rat model of CFA-induced arthritis, and the relations between DGHT-induced analgesia and endogenous nitric oxide(NO) and inducible NO synthase(iNOS)/neuronal NOS. Methods : CFA-induced arthritis model used to test the effect of DGHT was chronic pain model. After the induction of arthritis, rats subsequently showed a reduced stepping force of the affected limb for at least the next 18 days. the reduced stepping force of the limb was presumably due to a painful knee. DGHT dissolved in water was orally administrated. After the treatment, behavioral tests measuring stepping force were periodically conducted during the next 4 hours. Results : DGHT produced significant improvement of stepping force of the hindlimb affected by the arthritis lasting at least 2 hours. DGHT produced the improvement of stepping force of the affected hindlimb in a dose-dependent manner. Both NO production and nNOS/iNOS protein expression which is increased by arthritis were suppressed by DGHT administration. Conclusions : The data suggest 1) that DGHT produces a potent analgesic effect on the chronic knee arthritis pain model in the rat and 2) that DGHT-induced analgesia modulate endogenous NO through the suppression of nNOS/iNOS protein expression.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.60-70
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• 2000

In this paper a 3D position measuring device that finds the 3D position of an arbitarily placed object using a camersa system is introduced. The camera system consists of three stepping motors and a CCD camera and a laser. The viewing direction of the camera is controlled by two stepping motors (pan and tilt motors) and the direction of a laser is also controlled by a stepping motors(laser motor). If an object in a remote place is selected from a live video image the x,y,z coordinates of the object with respect to the reference coordinate system can be obtained by calculating the distance from the camera to the object using a structured light scheme and by obtaining the orientation of the camera that is controlled by two stepping motors. The angles o f stepping motors are controlled by a SGI O2 workstation through a parallel port. The mathematical model of the camera and the distance measuring system are calibrated to calculate an accurate position of the object. This 3D position measuring device can be used to acquire information that is necessary to monitor a remote place.

• Proceedings of the KIEE Conference
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• summer
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• pp.929-931
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• 2004

Recently, there are growing demands for permanent magnet(PM) type stepping motor that greater mechanical output, smaller size. Especially, the PM type stepping motor with claw-poles is preferred solution for many small electronics position determination devices since it is small in size, low cost. But, the design of the PM type stepping motor with claw-poles is very difficult because it has a magnetic 3-D shape. This paper deals with a study of the miniaturization of the PM type stepping motor with claw-poles. We investigate the characteristic of the actual model using the equivalent magnetic circuit method and 3-D FE analysis.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.2
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• pp.15-21
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• 2001

This paper presents an improved characteristic analysis methodology for a 5-phase hybrid stepping motor. The basic approach is based on the use of equivalent magnetic circuit taking into account the localized saturation throughout the hybrid stepping motor. The finite element method(FEM) is used to generate the magnetic circuit parameters for the complex stator and rotor teeth and airgap considering the saturation effects in tooth and poles. In addition, the neural network is used to map a change of parameters and predicts their approximation. Therefore, the proposed method efficiently improves the accuracy of analysis by using the parameter characterizing localized saturation effects and reduces the computational time by using the neural network. An improved circuit model of 5-phase hybrid stepping motor is presented and its application is provided to demonstrate the effectiveness of the proposed method.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.3
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• pp.301-306
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• 2021

In this paper, we propose a modified back-stepping control method in view of the dynamic model of mobile manipulator has the nonholonomic constraints, these constraints should be considered to design a tracking controller for the mobile manipulator. The conventional back-stepping controller includes the dynamics and kinematics of the mobile robot systems. and the modified adaptive back0stepping method is applied to constructing the controller. The proposed controller can realize the tracking trajectory of the reference path. The efficiency and robustness of this control method is demonstrated by the simulation.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.39-42
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• 2005

Though full 3D analysis is the proper method to analyze the hybrid stepping motor (HSM), it has weak points in the areas of computation time and complexity. This paper introduces 2D FEA using a virtual magnetic barrier for the axial cross section to save computation time. For the purpose of 2D FEA, the virtual magnetic barrier and equivalent permanent magnet model of HSM are proposed. This result is compared with that of experimental and 3D analysis, considered as a reference result.